Cannabidiol, commonly known as CBD, has been steadily gaining popularity as both a medical treatment and a health and wellness ingredient since cannabis legalization last fall. The non-psychoactive cannabinoid has been shown to be beneficial for a variety of conditions, especially anxiety, inflammation and pain management.
How CBD works in the body
Studies have shown that CBD works differently in the body than other cannabinoids, specifically affecting the liver cytochrome P450 pathway. Cannabidiol has the potential to inhibit or amplify any drug that uses the pathway, though the severity of those effects have yet to be studied, says Dr. Sana-Ara Ahmed, a practicing clinical anesthesiologist in Alberta and Ontario with specialist training in interventional chronic pain and cannabinoid medicine.
Dr. Ahmed explains that any drug metabolized through the cytochrome P450 pathway will be affected by the consumption of CBD or THC (tetrahydrocannabinol), leaving the potential for adverse interaction.
It isn’t as alarming as it sounds, though. There are common and safe compounds, like grapefruit juice, that also alter the enzymes in the cytochrome P450 pathway, Jessie Gill, a registered nurse with a background in holistic health and hospice, and the cannabis advocate behind Marijuana Mommy, notes in an e-mail response to The GrowthOp. The difference is those interactions are known, information is available and warning labels are used.
Known CBD and pharmaceutical drug interactions
Due to lack of clinical research, there is a long way to go in understanding the nature of these interactions. That said, there is currently evidence of certain interactions, including the following:
There is an increased risk of bleeding for people who are taking blood-thinning medications such as warfarin, ibuprofen, coumadin and others. CBD increases the potency of these medications and prolongs their duration in the body, so should be monitored. Blood thinners should not be combined with CBD without consulting with a healthcare provider.
CBD does not possess the sedative properties of THC, though a 2006 study showed that it did positively affect the sleep cycle. When CBD is combined with a sedative, or drug with sedating properties, it has an additive effect, increasing the potency of the medication. This interaction needs to be considered when determining dosing.
Lowered efficiency in medications
CBD is also known to decrease the effectiveness of certain medications. Pharmaceuticals that are subject to precise dosing requirements are susceptible to disruption from CBD. Despite speculation that CBD reduces the potency of anesthetic, Dr. Ahmed says the issue has not yet been well studied so it’s too soon to reach conclusions one way or the other.
The higher the dose, the higher the potential risk
No medication comes without potential side effects, and CBD is no exception. Gill points out that adverse reactions to CBD are rare, but have been seen in clinical research. Side effects of CBD include anxiety, fatigue, diarrhea and appetite changes, and seem to be dependent on the volume of the dose.
“We don’t expect interactions with lower doses of CBD, but the potential is something all consumers should be aware of,” Gill writes. “Consumers should add CBD to their care plan slowly, starting at a low dose and increasing gradually,” she notes. It appears the higher the dose—she writes some studies cite up to 800 mgs a day—the greater the risk of experiencing side effects.
Be honest with your doctor
There is still so much to be learned on how much CBD interacts with other drugs, making it essential to have an open dialogue with your physician. Mitigating side effects could be as simple as taking CBD doses several hours apart from pharmaceutical doses.
Dr. Ahmed cites the importance of disclosing cannabis use with a doctor, sharing that even something as simple as an anti-fungal treatment for a yeast infection can be impacted. Since CBD can interact with multiple medications in a variety of ways, a family doctor is the best person to discuss potential drug interactions.